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CVE-2026-49440

Deno: Miller-Rabin Primality Test Allows Zero Rounds

Published: Jun 23, 2026Updated: Jun 26, 2026 Sources: CVE List NVDCWE-325
7.4HIGH
NVD MITRE
EPSS Score
0.1%
Top 95.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
Not available

Description

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, node:crypto.checkPrime(candidate[, options][, callback]) and crypto.checkPrimeSync(candidate[, options]) ran no Miller-Rabin rounds at all when the caller left options.checks at its default of 0. In that mode, the only test applied to the candidate was trial division by the primes up to 17,863. Any composite whose smallest prime factor exceeds that bound — for example the product of two primes just above it, such as 17,881 × 17,891 — was reported as true ("probably prime"). The same divergence affected the lower-level op_node_check_prime / op_node_check_prime_bytes paths that the polyfill calls into. This vulnerability is fixed in 2.8.1.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-325

Affected Products

denoland
oss-project·USaka deno
denoOn-prem
OSS Libraries / generic-library
deno
oss-projectaka deno standard modules, deno runtime
denoLibrary
OSS Libraries / generic-library

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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References

https://github.com/denoland/deno/security/advisories/GHSA-9xg4-qhm4-g43w
github.com
https://github.com/denoland/deno/pull/34391
github.com

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